program cifra;
var t,n,i,j,s,l,k,l1:longint;
    f,g:text;
begin
assign(f,'cifra.in');
reset(f);
assign(g,'cifra.out');
rewrite(g);
read(f,t);
for i:=1 to t do
  begin
    s:=0;
    read(f,n);
    for j:=1 to n do
      begin
        l:=j;
        l1:=j;
        for k:=2 to (j mod 10) do
          l:=((l mod 10)*(l1 mod 10))mod 10;
        inc(s,l);
        s:=s mod 10;
      end;
    writeln(g,s);
  end;
close(f);
close(g);
end.